Machines for servicing tires are generally well known devices. A typical machine comprises a mechanical system which clamps the wheel on a supporting structure and then, a tire changing tool removes or installs the tire on the wheel. The mechanical system for clamping the wheel includes a vertical treaded rod extending through the central opening of the wheel and receiving a large nut pressing down the wheel on the supporting structure.
Such tire changing machines are, however, unable to service tires on wheels without a central opening. Therefore, in the recent years, manufacturers of tire servicing equipment have developed universal tire changing machines which operate according to a different principle. Such machines includes a rotatable table, driven by an electric motor or by a pneumatic system, and carrying a plurality of movable clamping jaws which engage the inner wall of the wheel to hold it on the table. During a tire servicing operation, a rotational movement is imparted to the table while a stationary tire changing tool dismounts or mounts the tire on the wheel.
During the installation of a new tire, the first operation is to loosely mount the tire on the wheel by using the tire changing tool. Subsequently, compressed air is injected through the valve of the wheel to seat the tire beads against the rim portions of the wheel and inflate the tire.
With the increasing popularity of low profile radial tires with more rigid sidewalls, problems have been experienced for seating the beads of these tires to the rims of the wheel. To overcome these problems, different air injection systems have been desiged to be mounted on the rotatable table for injecting air through a plurality of discharge nozzles, at a substantially high pressure, between the interface of the tire bead and the rim of the wheel, which are adjacent to the top surface of the table. These systems, however, have not been very successful and their practical implementation has been rather limited for a number of reasons. One of these reasons is that they are too costly to manufacture and also they are of such design that they constitute a very tortuous path for the compressed air, substantially reducing its pressure at the discharge nozzles.